A liquid crystal display panel of a liquid crystal display device does not emit light, so a surface light source needs to be provided by a backlight module. The backlight module includes a direct type backlight module and a side edge backlight module. A current common side edge backlight module is to dispose a light emitting diode (LED) light bar on a side of a light guide plate, and there are a plurality of dots inside the light guide plate. After a light beam provided by the LED light bar enters the light guide plate, the light beam is then emitted from a light exit surface of the light guide plate by the dots. However, since the LED light bar is disposed on the side of the light guide plate, uneven brightness occurs easily, which is not conducive to local dimming.
A current common direct type backlight module is to dispose a plurality of LEDs arranged in a two-dimensional array under a diffusion plate. In order to reduce a quantity of LEDs, a secondary lens is provided corresponding to each LED to increase a light emitting angle of the LED. Compared with the side edge backlight module, the direct type backlight module has better brightness uniformity and is advantageous for local dimming, but with a problem of thicker thickness.
A conventional technology has also developed another hybrid backlight module, which mainly uses a light guide plate to hollow out and place a light emitting diode instead of the secondary lens used in the direct type backlight module to reduce an overall thickness of the hybrid backlight module. However, corners of each light guide plate have apparent dark areas easily, and light leakage is easily formed at edges of each light guide plate. Therefore, the conventional hybrid backlight module has a problem of uneven brightness.
The information disclosed in this “BACKGROUND OF THE INVENTION” section is only for enhancement understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Furthermore, the information disclosed in this “BACKGROUND OF THE INVENTION” section does not mean that one or more problems to be solved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art.